Gaseous fuel feed systems, with automatic starting and idling control, for internal combustion engines



ENslGN l2,896,599

5 sheets-Sheet 1 COMBUSTION ENGINES July 2s, 1959 GASEOUS FUEL FEED SYSTEMS, WITH AUTOMATIC STARTING AND IDLING CONTROL. FOR INTERNAL Filed May 19, 1958 July 28, 1959 R. F. ENslGN 2,896,599

GAsEous FUEL FEED sYsTENs, wITH AUTOMATIC STARTING I AND IDLINc- CONTROL, EOE INTERNAL COMBUSTI ON ENGINES 5 Sheets-She v 2 Filed May 19, 1958 INVENTOR. oy Il KMS/6N July 28, 1959 R. F. ENSIGN 2,896,599

GASEOUS FUEL FEED SYSTEMS, WITH AUTOMATIC STARTING AND IDLING CONTROL, FOR INTERNAL COMBUSTION ENGINES 5 Sheets-Sheet 3 Filed May 19,4 1958 Jff July 28, 1959 v R. F. r-:NslGN 2,396,599y

- GAsEous FUEL EEE@ SYSTEMS, WITH AUTOMATIC STAETTNG AND IDLING CONTROL, FOR INTERNAL COMBUSTION ENGINES 5 SheeTS-sheeT 4 Filed May 19, 1958 July 2 8, 1959 R. F. ENslGN 2,896,599

GAsEous FUEL FEED SYSTEMS, wITH AUTOMATIC STARTING: IDLTING CONTROL, FOR INTERNAL coMBusTToN ENGINES Filed May 19, 1958 V5 Sheets-Sheet `5 74 Zi/G4 9g 60 T 76 I 7 foo f 104 l E: 5%/27 f2 j 43j IGI 104 fa/ .d/L

i l fj" 122 79.9 767 f/Z 44 1&7 lge# 32 45 asf :56

26e l o L j?? Rox [.j lf2 BY L I iff/2% 9 mf GASEOUS FEED SYSTEMS, WITH AUTO- MATIC STARTING AND IDIJING CNTROL, FOR INTERNAL COMBUSTION ENGINES Roy F. Ensign, Fullerton, Calif., assignor to Ensign Carburetor Company, Fullerton, Calif., a corporation of California Application May 19, 1958, Serial No`."736,321

`2'; claims. (ci. 12s-1z0) This application is a continuation ,in partof my co- Uifed States Patent ject Yto known modication controls which may be applied a minus pressure of` about one-quarter inch of water. p t

That is done by biasing the diaphragm-valve system of the regulator (of the last stage in a multiple stage regulator) in a valve `closing direction by a force that makes it necessary to lower the pressure in the regulator delivery chamber by that, say, quarter inch of water, below a refference pressure acting on the outer face of the diaphragm, in order to put the valve system in balance ready to open and feed fuel. The reference `pressure on the outer face of the diaphragm is commonly atmospheric or the pressure existent at the carbureter air intake. And when the engine is standing, with equal pressures on opposite faces of the diaphragm, the valve is held closed by theV biasing force.

On starting turn-over with the throttle closed, .to or near to, idling position, and at idling, the velocity de.- pression at the venturi throat is commonly less` than that quarter inch of water; and so, special arrangements such as chokes and idling by-passes or` other controls are commonly used for starting `and idling,

The present invention," in one of its typicalv forms, provides that, under a valvular control actuated by-virtues of engine operation, gaseous pressure from a constant high pressure source (at a pressure higher than atmospheric or the air intake pressure) is applied to raise or control L ings in which:`

the normal delivery pressure, regardless of what that normal pressure may be. In certain forms of the` system that higher pressure is applied to a reference` chamber of the regulator diaphragm to increase the opening force on the regulator valve by the desired amount to put it in balance, or substantially so, oreven to open `it slightly; so that the small venturi throat depression can then draw fuel from the delivery chamber. That action of balancing the regulator takes place uniformly throughout all stages of engine operation, including starting `turn-over, idling and operation through all mediumand full power ranges. The regulator then operates uniformlyto supply fuel to the venturi in uniform' proportion to the air iiow, at all stages of operation. That'uniforr'n proportion may, of course, be modified if desiredby additional provisions such, for instance, as an econoinizer.`

v j, 2,896,599 Patented July V28,

ICC

However, the regulator may be set to normally deliver at, or somewhat above, atmospheric pressure; In such a system the invention provides for shutting off fuel de'- livery when the engine is standing by a cut-olf valve on the initial regulator feed, that valve being. controlled by Virtue of engine operation. And that valve then controls the actuation of the meanswhich, by application of pressure to a reference pressure chamber, sets and controls the delivery pressure of theregulator throughout engine operation. fr 't f f f fIhere are several preferred features of the invention. One such preferred features is that the `high pressure source is a higher pressure stage of a multiple-stagere'gulator, the last stage of which delivers to theventuri. Y In a two-stage regulator, for example, the iirst stage pressure, substantially uniform, is necessarily higherthan the pressure existent at the carbureter air intake. j Broadly, however, the high pressure source may be anyV suitable and preferably regulated source, and the regulator may be single stage. 9 f

It is also preferred that the required reference pressure be obtained by feeding the high pressure to a regulator reference chamber at a fixed rate, and by bleeding gas from that chamber at a iixed rate, either or both rates being preferably adjustable. And the bleed may and preferably goes into the carburetor. t 't j The control valve may be actuated in various manners; in fact, by any means that insures its openingV whenever the engine is turning over and its closing when the engine is standing. Forinstance, thecontrolvalve may be operated by a diaphragm which is subjected to the depression existent in theintake manifold. With the throttle closed Idown to idling position, that depression is ordinarily suliicient to reliably operate the valve on starting turnover. But fforstarting it may be` desirable to open the throttle somewhat, and then, particularly with slowfturnover of a cold engine, the manifold depression may not be suiiicient to reliably operate the control valve. Consequently it may `bedesirable to actuate the valve by means actuated in the starting motor circuit, or the ignition circuit, and in the `forms where the control ofthe system is by an initial cut-off valve, the valve actuation is prefer.- ably electrical. The following detailed description sets out various illustrative preferred (forms that the yinvention may take, reference being had to the accompanying draw- Fig. l is a schematic showing of one form, where the control valve is actuated by manifold depression; Fig. lashows amodified form of` control valve; j p

Fig. 2 is a schematic showing how the control Yvalve mayalso be actuated in the starter motor circuit; 't t Fig. 3 is a schematic showing thecontrol `valve actuated in the ignition circuit; y t Fig. 4 is a schematic similarto Fig. 1 showing modi,- iications; Figs. 5 and 6 are schematics showing modifications controlled by an initialrshut-olfvalve; Fig 7 is a schematic similarto Fig. 4, showing modifications;

Fig. 8 showsoa modified control circuit; and Figs. 9 and 1.0 show other modified systems. In Fig. l, 10 represents any conventional carburetor and 12 any conventional two-stage pressure regulator.V The carburetor is shown with an air and mixture passage 13, with air intake 14, venturi throat 16, throttle 18,and

further the engine intake manifold is indicated at 20.

Y' ence pressure tending to open valve 282 in this case mainly the 4pressure ofreference spring 32. The pressure in first stage chamber y24 is commonly set Ato be about eight or ten p.s.i. above atmospheric; in practise it must necessarily be above the pressure existent at the carbureter vair" intake.Y Thep'ressure in reference chamber 31 on the outer face of diaphragm 30 is commonly atmospheric, and may be so'here; but see below.

.The second stageof'the regulator is shown as havinga delivery chamber'36 of which the second stage diaphragm `38 forms one wall. That diaphragm operates the second vstage, valve l40 'that controls the passage 42 leading from tlrefirst vto the second stage chamber.' The connection between 38"and 40 i's shown inthe form of a lever 44. Movement Vof diaphragm .38 into chamber 36 causes valve f40 'to open. A spring46jtends to close the valve, biasing it closed when 'pressures on 'oppositefaces of diaphragm '38am-equal.

The outer face of diaphragm 38 is exposed to the 'liuid pressure in a 'reference chamber 50. Communicating with'fthat reference 'chamber'is a balance Vtube S2 which, preferably, with a Pitot `formation 54 on its end, picksup the total pressure in the air intake 14. If the air intake is wide open and unobstructed that balance tube is in full effect simply a communication of 50 with atmospheric'pressure. Air intakes are ordinarily obstructed, e.g. by air cleaners; and in anysuch case the rbalance tubeas shown picks up the actual effective pressure at jthe intake. jDelivery chamber 36 has an outlet through ytube 56 leading to vfuel nozzle 58 at the venturi throat. With thev engine standing, diaphragm 38y is subjected jto equal fluid pressures, atmospheric, on its opposite 'faces and in this form spring 46 then holds valve 40 closed by a force equal to the opening force extertible on Vthe valve by'a uid pressure of, say, one-quarter inch "of'water on the outer face of diaphragm 38. Consequently, "in this regulator arrangement, the pressure in delivery chamber 36 has `to Abe that much lower `than 'in'eference-chamber 50 in order to put the diaphragmvalve system in balance so that a slight suction through 56iwil1 lower' thepressure in 36 enough to causethe valve fto open. Y f V The system asso far ldescribed is typical of gaseous 'ffu'elf'eedsrnow in use. My invention, in' one of its forms, lies I'inthel combination withsuch known systems of the additionalrfeatures'now to bedescribed with reference "to the typical and illustrative showings in the drawings.

`InfFirg. 11,V a valve, generally designated 60, has a ldiaphragm v62 Vexposed on one 'face `to fluid pressure in chamber 64.V Its opposite face carriesl avalve p ad 66 which is seated on a valve seat 68 by the pressure of 'spring`7tl operating on theY diaphragm. A port 72, controlled 4preferably by an adjustably restrictive needle valve 74, 'leads to valve seat 68. A tube 76 connects the pressure'sourc'e, in this instance 4the first stage chamber '24, with that restricted port. A tube 78 connects the chamber 80, intol which valve v66, i68 discharges, to the second stage reference chamber 50. A tube 82 connectsdaphragm chamber-64 of the vvalve to the engine intake manifold by connecting with mixture passage 13 atlapoirit which is shownA here as always beyond the throttle. If an air cleaner or other pressure dropping obstruction is applied to-air `intake 14, as illustrated in other figures, the connection of 82 may beat any Vpoint in the air and mixture passage beyond that obstruction.

The communicating Ypassages 76 and 78, the port 72 and chamber 80 are -preferably all large enough in effective cross-section, asl compared with the effective crosssection of the restricted passage at the valve 74, that the restriction at 74 has effective control over the rate of gas flow through those passages. And the passage in tube 78 between chambers 80 and 36 should be fairly large for other reasons referred to below. Spring 70 is strong enough to hold valve pad 66 tightly on its seat against the pressure exerted on it by the fiuid pressure in .port 72 plus whatever rpressure. there is on the diaphragm in chamber 80. And preferably the spring is vs'o 'set or chosen, and the effective area 'of diaphragm 62 is such, that, on the application to chamber 64 of the least manifold depression that occurs in any operation of the engine (typically, a low starting turn-over depression of, say, three inches or less of water) with the throttle closed or nearly so (or with the throttle open, if .the air intake isobstructed) the valve will open widely enough that the effective valve opening is large as vcompared with the Yeffective opening at the restriction 74.

-Those vprovisions Vleave the control of the effective size of the passage between 24 and50 at the settable oradjustable orifice at 74, and regardless of how much wider valve 66 may open under depressions higher than the chosen minimum. lf the valve is limited in its opening, as by stops 65 for instance, and if ythe arrangement is such that the valve is always opened to its full stopped opening by the least manifold depression, the valve opening need only belarge enough as, preferably, to leave control of the passage with the adjustable restriction at 74.

The passage in balance tube 52 preferably has an oritice bushing '84, or other settable or adjustable restriction that controls Vthe effective size of that bleeding passage that bleeds reference chamber 50. Or, the passage size of tube S2 may itself constitute a bleed orifice of chosen fixed size. That bleeding orifice may be and preferably is jfairly small; for example it may be about three-sixteenths inch diameter in a system feeding an inchanda` quarter sizeV c'arbureter.

' Operation is as follows. The orifice at valve 74 is so set in size with relation to the size of the bleed orifice 84 that the pressure vin reference chamber 50, with valve 60 open, will be raised above what it otherwise is by about the amount that the normal delivery pressure in 36 is below the pressure in 50 with valve 60 closed. A practical manner of making that setting is described just below. Assuming that the setting is approximately correct, then on turning over to start, valve 60 opens and 'the reference pressure in 50 tending to open regulator valve 40 is immediately increased by approximately the amount that the normal delivery pressure is below the pressure existent at the air intake. Thatputs Vthe diaphragm-valve system 38, 40 approximately in balance so that the slight venturi throat depression will draw in fuel Ito `start the engine with the throttle in or near idling position.

As soon as the engine is idling fine adjustment at valve 74 can then be made to slightly vary the pressure in'50 to obtain"the bestidlingv mixture. It has been found that, usually, adjustment of 74 at normal idling speed is sufficient. But, if desired, similar slight adjustment can bemade at 74 to obtain the best mixture through medium operating ranges. When Veither of-those, things is done and themixturelremains approximately constant through alln operating ranges, it is vknown that the regulator is very closely in balance to deliver at the pressure existent at the air intake; that is, the pressure in reference chamber `501is approximately as much vabove the air intake lpressure as the normal delivery pressure of the regulator is lbelow that air intake pressure.

vDuring operation a small constant amount of gas flows intothe carburetort-hrough bleed orifice 84. With the regulator imbalance-the venturi throat depressiondraws in fuel Iat'58 in fixed ratio lto Ythe airflow throughout all stages of operation. The small bleed -at 84 adds a small constant amount of gas, flowing under the difference in pressure between 50 and `the -air intake--a difference in practice of about one-quarter Ainch of water. Preferably that constant amount is only a small fraction of the full amount required Ifor idling. l

JrA's a'result'oflthat constant small fuel flow, the mixture at starting and idling is slightly .richer than that through medium and heavy ranges; At thosey ranges the constant bleed tlow is negligible.v Consequently if adjustment at l 74' is 'made lfuor ideal mixture proportions through medium ranges, theidling and starting mixture will be slightly rich, which, if anything, is desirable. If, on the other hand, the fnal adjustment is made for ideal proportions at idling, the mixture through the medium and heavy ,ranges will be slightly lean, which also may be desirable.

Or a compromise adjustment maybe made between the two conditions. The diierence between the idling and medium range proportions may be made so slight as to be negligible by reducing the size of bleed 84.

As `has been mentioned, the source of higher pressure may be any suitable source. Thus the lirst stage cham` ber 24 of Fig. l may be viewed simply as a pressure source for the second stage of the regulator and -for `feed to valve `60. In all essentials the regulator may be one of single stage. And this observation applies toany of the system forms hereinafter described.

lIt may Ialso be noted that the action of controlling the delivery pressure of the" regulator is the same regardless of the normal delivery pressure for 'which the regulator is set. Thus, the regulator of Fig. 1 may beset to normally deliver at, say, atmospheric pressure or even slightly above. In that event its delivery may be shut oft, and opened under engine control, by the shut-olf system to be described later.

The passage in tube 78 should be, as noted above, fairly large; large enough to Ifreely pass the pressure in valve chamber 80 to the relatively large chamber 50. Otherwise the pressure in `80 may delay Ithe closing of valve 66 after the engine stops operating.

It will be understood that the high pressure -fuel feed at 120 to the first stage of the regulator may be in fully gaseous form. However, the high pressure 'fuel usually used in such systems as here described is typically butane, which, at ordinary atmospheric temperatures is in liquid form at the high pressure. Upon release of that high pressure to the much lower pressure in lrst stage chamber 24, the fuel ordinarily vaporizes; the heat of vaporization in .a small regulator being supplied by conduction and radition Ifrom the atmosphere and the surroundings, or in a regulator of large capacity being supplied by applied heat. In some instances the .fuel may not completely vaporize in 24, some -ne misty globules remaining in liquid form. In such a case it may 4be desirable, if not necessary, that the communication 76 shall take olf from lirst stage chamber 24 at a point where only Vfully vaporized gas will llow into itand thence past the orice at 74. If there is any cfuel in liquid phase in lirst stage chamber 24, and if liquid globules tlow past the restriction at 74, their subsequent vaporization will uncontrollably vary the pressure in 50. To prevent that the take-olf of 76 may preferably be so located :or shielded that globules will not enter it. Such location or shielding will depend upon the Iphysical construction of, and the how paths `of the uids in, any -actual regulator. In the purely schematic showing here that prevention is illustrated by the shield 75 which shields 76 from the How going to 42 and places the intake of 75 in a quiescent zone where any globules which may rind their way behind the shield will have time enough to vaporize there or in passage 76 before passing the restriction at 74.

' It will be understood also, that inregulators of the type and use here described, that if an initially liquid fuel such as butane vdoes not =fully vaporize in first stage chamber 24, it is completely vaporized in second stage chamber 36 at its lower pressure, with` heat of vaporization supplied as above stated.

As so far described, the pressure at the source of high pressure (the rst stage of the regulator here) is a pressure that is constant with relation to atmospheric pressure, reference chamber 31 being open to atmosphere. The pressure in air intake 14 may Vary slightly with relation to atmospheric, due to variations in the action of eg. Ia cleaner on the intake. Ordinarily those variations are a very small Vpercentage kof the total pressure drop between 24 and the air intake, `and therefore will'have a` negligible effect on the pressure maintained in 50. However, those slight variations may be eliminated if desired by yapplying air intake pressure to reference charnber 31, which will keep the pressure in 24 at a xed ligure with relation to the intake pressure `rather than with relation to atmospheric. That is done simply by lapplying the balance pressure picked up by 54 to chamber 31; as by the balance `connection 52a.

Fig. la shows a variant .form of valve 60. In that ligure, the communicatingpassages 76, 78 and 82 correspond to those passages in Fig. 1. Tube 82, connecting to the air and mixture passage, communicates with chamber 64a at the back of diaphragm 62a, and the manifold depression draws the diaphragm back (up, intheiigure) against the pressure of spring 70a. 'Ihe` chamber 64b below the diaphragm is open to atmosphere, so that the whole depression in 82 below atmosphere, including any depression due to air intake obstruction, `is available to operate the diaphragm. With this form of valve `the throttle need not be closed down for starting, the diaphragm then being operated solely by the pressure drop dueto e.g. an air cleaner.

A wall 601 divides chamber 64b from chamber 80b, and a valve stem 66a secured to diaphragm 62aextends movably through that wall and carries valve closure 66b in chamber h. A passage 72a is fed with uid under pressure 4from passage 76 under control of valve 74a and has a valve seat `68a under valve closure 66b. Normally closure 66b is pressed against seat 68a by spring 70a, closing passage 72a. On application of manifold depression to chamber 64a diaphragm `62a moves valve closure 66h up, opening passage 72a to deliver pressure fluid to passage 78 that goes to reference chamber 50. In its upper position 66b seats on seat 68h to seal the opening through which stern 66a passes through wall 601.

' It is often desirable, to insure quick starting of an engine, to open 4the throttle somewhat beyond the idling po-v sition. When that is done, the manifold depression may become so small that it cannot be relied upon to operate the control valve 60 unless its diaphragm 62 is made very large, which is undesirable. Fig. 2 shows one arrangement for overcoming` that dithcutly and for insuring quick starting -with the throttle opened.

In that ligure the `control valve 60a is similar to the form, with that plate, a closed magnetic circuit except for the short gaps at the plate. The gap spacing may be such that the core and sheath form the stops which limit the opening of valve 66 in the same manner as described for stops 65 in Fig. 1. The inner end of winding 92 may be grounded, and its outer end connected, as by conductor 96, into the circuit of startermotor 98. As schematically indicated here, the starter switchv controls; supply of current from battery 102 to both the starter motor and, via 96, to the winding 92. That winding is thus energized as long as the starter motor is energized. Energization of the electromagnet causes ,it to attract plate 63, opening valve 66 immediately and holding `it open as long as switch 100 is closed. When the engine starts switch 100 is opened; but, with. theengine then turning over at normal idling or faster, the manifold depression applied via 82' is then ample to hold valve 664 open. Spring 70 may be set to exert about the same pressure as before described so that the small manifold depression occurring at low speed lugging will still holdthe valve open.

' Fig. 3 shows other-arrangements for opening the con-fv trol valve and holding1 it open. In that iigure the` valve 60a anditsappurtenancesA arethe same asin Fig. 2 and are lgiven-the vsame numerals.V The magnetwinding 92 ishere connected.r into the primary circuit of the engine ignition system. VAs; schematically shown, a conductor 110 connects.I the live side. of the winding into conductor 112 which is controlled by ignition switch 114. For the moment disregarding the switch shown at 116, and assuming that 110 is directly connected to 112, the magnet Winding will be energized and valver 60a held open at allA times that the ignition switch is closedthat is, at allotimes. during starting turn-over and all other phases of. engine operation.. Accordingly, in this systemy of Fig. 3. the manifold depression need not be depended upon at all for either'openingl the valve or holding it open, and the manifold connection 82 to valve 60a can if desired bey dispensedfwith. However, in the preferred form of thevsystemf` described below the manifold depression holds valve. 60a open. u

Fig. 3 also incorporates the starter circuit, and a shutoft valve 122 in the high pressure feed line 120 leading to the regulator. Asthere schematically shown, valve 1'22 is a normally closed valve openedV by solenoid 124 whenenergized viay conductor 112. Ignoring switch 116, valve 122 will always be open when the ignition switch is. closed. The startercircuit. includes switch 100 which energizes starter motor 9.8 and also energizes lines 110 and 112 via line 111. Closure of starter switch 100` will thus also open valve 60a, and, again assuming 111 to be connectedto 112, will also open shut-off valve 122.

Preferably, a manifold actuated switch 116 is interposed inv line. 112 and its connection to line 110. lAs schematically shown in Fig. 3, a small diaphragm chamber 117 is communicated with the manifold via 82. Diaphragm 118 is pressedY out by a light spring 119 and,

normally holds. switch` 116 in the illustrated position connecting line 111 to 1170 and 112 leading to valve 60a andshut-otf valve 122. Closure of the starting switch thus. opens valve 60a. and shut-olf 122. As soon as the engine is turning. over, or starts, diaphragm 118 moves in and moves switch 116 to a position to break the connection of 111 withY 110- and; 112fandl to close the line 112 leading from the ignition circuit. Closure of ignition switch 114 during engine turn-over and operation consequently holds. valve 60a and shut-off 122 open dur-v not drawing in the fuel that passes through the valve.V

If the engine is not operating, switch 116 breaks the connection of the ignition circuit to both valve 60a and shutoh 122. With both those valves closed there is a double shut-'off preventing. leakage through the regulator.

As inl Fig.. 2, the engine may be started with open throttle, Without the. necessity of making switch 116 respond to the very light manifold depression existing on. starting turn-over. Once the engine has started, the increased manifold depression holds valve 60u; open and the ignition circuit holds cut-olf 122 and also valve 60a open. l

' With, such a. cut-offy Valve in the initial feed to the regulator, its normal delivery pressure need not be subatmospheric in. ordertoshut off. fuel delivery (beyond the small amount contained in the regulator chamber) with *the engine standing. Regardless of what the normal delivery pressure may be, the system acts to control thatr delivery pressure. This same cut-off system is shown alsoin Fig. l. andr other iigures to be described, and the same remarks apply to them.

- Thesame electrically controlledshut-otf for the initial feed to the regulator may be incorporated in the system of.lg,.1.. As. thereshQwntheshut-oi valve 122 isin 8, thev same crcuiting. with theignitionand starter switchesS and switch 116; with/the same controlofrthe; shut-oli valve. As discussed; later on in connection with. other forms of the system, the shut-olf valve' actuated'by engine turn-over, may be4 the; control-lingA element in raising, the delivery pressure ofy the regulator. In Fig; 1,. with: the initial shut-off 122,V there is a doubleshut-off of the, high pressure preventing leakage through the regulator.. with the engine. standing;` both valves 122-andv 60. then. being closed'. Eachr of those valves, is an engine. controlled means for applying pressure to thev reference chamber. This.: is` also true of all the systems here de scribed, excepting only that of Fig. 5 where the cut-off. valve 122 solely performs the engine-controlledkactu# ation. of the system..y x Y v ,It has been mentioned before that the high pressure that is applied to the referencel chambers may come di;- rectly from any' suitable. high pressure. source. Thus, in Fig. l, valve 60 may be fed with pressure fluid directly;v from the supplyand the regulatory may be single, stage. This is true. of all the variant forms of my system shown here. Y

Fig.y 4 shows a system similar'generally to that of Fig., l but with further modifications. The parts similar to.. those of Fig. l are given the same numerals.

vIn Fig. 4 the carbureter air intake 14 is schematically shown equipped with an obstruction, illustratively inthe form of an air cleaner 15, in which, by the depression of an oil level4 such as that at 13 in order. topass air to the intake, a definite drop in pressure below-atmos-l pheric isl imposedl on the air entering intake 14- and. passing through the carburetor tothe engine'y manifold. And; the valve 60'b, performing generally the same functions as 60 in Fig. 1, is actuated at least partly, or even wholly., by that pressure drop; and sol also is the diaphragm y118. that operates switch 116. Hereinafter, in referring, to an air cleaner, an obstruction suicient for the described. operation is intended.

Valve 60h, as here shown, has aI diaphragm chamber` 64o of which diaphragm 62a` forms one wall with its. outer face exposed` to atmospheric pressure via opening, 62d. Passage 82 communicates with chamber 64C.

A valve stem 66d extends movably through wall 602` of chamber 64e. and projects into a valve chamber 80e; where, by-movementdownward, (inthe figure) it presses. down onl the hat spring 70e that normally holds valve` pad 66C in a position closing the communication between. passage 72e `and chamber 80o. The feed of glas from, passage 76 to passage 72e is adjusted. by valve 74e, audi passage 78 takes gas fromk chamber 80a` to pass it torefer ence chamber 50; On downward movement of diaphragm 62o to open the valve at 66e, another valve. formationI 66e seals oi any leakage around thevalve stem whereyit. passes through wall 602. p

In this arrangement, passage 82,A and also the passage.- 82C that goes to the diaphragm chamber 11-17 operating; switch 116, may communicate with the air and-mixturepassage at any point lbeyond the pressure-dropping obstruction i15, either ahead of the throttle. or beyond it; The. same remarks apply to themodiiied -form of valveV 60:l shown in Fig. la. Connected at any point beyondv the1ob struction in Fig. 4, the valve 60h and theswitch operating diaphragm 118 are: actuated; by the pressure dropv duet` to the obstruction, and` will be operated during starting turn-over at open throttle and. then throughout all other ranges of engine operation.

Valve 60b of Fig. 4 is obviously applicable to the system of Fig. l. Y

Fig. 4 shows valve 40a, that controls the port* 42 leading from first stage chamber 24' to second stage chamber 36, opening against the pressure in 24 instead of with that pressure asin Fig. l. A light closing spring40bv carries and centers the valve, the valve stem being guidedv by guide 40e. Lever 44 bearson. thestemso thatm'ove'- against the pressure in 24.` v p This A.arrangement tends to stabilize' the pressure in 36 when the feed pressure in 24 varies. Pressure in 24' ltends, Iby pressure on the valve, to close it, and thus to reduce the pressure in 36.` YBut Athe reference pressure in 50, tending to open the valve, also varies as the valve closing pressuretin 24 varies.A Thus, if pressure in 24 increases, increasing the closing pressure onthe valve, the vincreased `pressurefin 24, fed to 50 `via valve 60, compensatingly increases the valve 4,opening pressure in 50. This arrangement of valve Y40is applicable to Fig. 1

ment of diaphragm 38 into chamber 36 opens'thevalive` and towall others where `the control exercised by feeding pressure to chamber 50`. p

Fig. 4 also shows a valvular unit be used in any Iof the other forms, to variably control thedelivery pressure in chamber 36 Vby varying the pressure in reference chamber 50. Unit 130 is inserted1 in thebalance tube 52.1'` Tube52 leads from reference chamber 50 to a diaphragmA chamber 132 of which the` small diaphragm 134 forms one wall.` Diaphragm-'134' falls by gravity or is pressed down by -a light spring and, with fthe system lat rest, is -in a lower position where pin 136 carried by it partially plugs the port 138 leading from chamber 132 to passage 140 from which balance tube 52 leads on to the air intake. Diaphragm 134 will be raised `by a small difference in pressure in 50 over thatat the air intake, say by a diierential of one-tenth inch of water. On initial actuation of the system, with pin 136 plugging hole 138, the bleedingcapacity oaf the bal-ance tube is reduced and pressure in 50 immediately builds up to raise pressure in 36 temporarily above that previously described in connection with Fig. l. The pressure in 50 above that at 14 then slowly raises diaphragm 134, the rate being controlled by a small bleed 142 leading from the 'back of the diaphragm. When pinl 136 is raised out of hole 138 the balance tube 52 bleeds more freely and the relative pressures in 50 and 36 fall to what has been previously described. The valve 130 may be used on any ofthe various forms described in this specification.

Fig. shows anotherarrangement for controllingthe delivery pressure of the regulator, controlled by engine operation. The parits similar to those shown in Figs. 1 and 4 are given the same numerals.

Control of shut-off valve 122 by the starter and ignition circuits and switch 116 is the same as in Figs. l, 3 and 4. As mentioned in connection 'with Fig. 4, the passage 82e can connect with the air and mixture passage at any point if an obstruction such as an airl cleaner is on the intake 14.

The valve biasing .spring 46 is omitted in Fig. 5 and livery 36 by wall 36e. Wall 36e has a leak port through which the pressures in 36d and 36 tend to equalize; that port lbeing conveniently formed at 36j where pin 43 passes loosely through the wall. Reference chamber 50 is connected to atmosphere, or the air intake, by balance tube 52, which in this instance needs no calibration;Y

On opening of shut-ovalve 122 by virtue of the engine turning over, pressure fluid is fed to the rst stage chamber 24 and, via 76d from that chamber to the reference chamber 36d. Fluid pressure on valve 40 tends to open it to raise the pressure in 36. Without the passage 76d, the pressure lin 36 would stabilize at a pressure rabove that in reference chamber 50 by an amount depending on the opening pressure on valve 40. i Needle` valve 74d is adjusted to feed pressure uid into reference.A chamber 36d at. a .rate that, bleeding` into 13m/that can-also i stabilized at the desired 4point.`

`1o 36 through 36j, willkeep pressure' in 36d above'ihaf in 36. Pressure in 36d tendsfto close valve 40'and lower the delivery pressure in 36.` By suitable adjustment of valve 74d the delivery pressure in 36 can be And it will be noted that here again the pressure in 36 will not vary with variations in pressure in 24 or in the initial supply line; for as the opening pressure on valve 40 v-aries, the valve closing pressure in 36dalso varies. It will be noted that the pressure in 36d bleeds, via 36 and :56, to the air and mixture passage; the bleed thus being similar to the bleed of referencechamber 50 in, for instance, Fig. 1. IA light spring 38a holds valve 40 open when there is l no pressure in 24. Then, when cut-oli 122 opens spring 38a holds valve 40' open as the pressure in 24 builds up, thus providing amomentary pulse of starting fuel indelivery chamber 36 before valve 40` closes. The amount of `the-pulse depends onhow` far spring 38a holds the valve open'. Such a spring will have the sameeffect in,`

" for example, `'such systems as that of Figs. 4 and 7 if the valve 60 were made to be a simple adjusted passage.` The valve 130 may also be used in this system of Fig. 5 to providea starting pulse; and also in that of Fig. 6.

When the engine stops, cut-oli valve 122 closes `and any fuel gas remaining in chamber 24 bleeds out through 76d and 36. When the engine again turns over, the wxhole system is put into operation by the opening of cut-off valve 122. In this and other similar forms or in p forms such as those of Figs. 1 and 4 if the normal de- 30` livery pressure is not sub-atmospheric, the whole, or initial, engine control of the pressure .controlling system is through the cut-oli valve.

A variant of the form of Fig. 5 is illustrated in the forms of Figs. l, 3 and 4. Assume, for example in Fig. l, that the valve 60 is eliminated or is always open so that 76 islalways connected with 78 and reference chamber 50. Val-ve 40 may or may not be biased closed by spring 46, so that the normal delivery pressure may be, say, atmospheric. Here again, the :system is put into operation to control and maintain the desired delivery pressure by the valve 122.

Fig. 6 shows another modification in which the leakage from chamber 24,'Iwhen the engine stops and shutoff 122 "is closed, is limited; and also in which the feed of pressure gas, instead of going to the sub-chamber 36d otf Fig.- 5, goes to thereference chamber 50 'as in e.g.` Figs. 1 and 4.

In Fig. l6 the electrical controls of shut-olf 122 are the same las in the other figures. xas having a valve 40a like that in Fig. 4. Its normal delivery pressure may be atmospheric or subdatmospheric.

Valve-60g has a diaphragm chamber y64g to which passage 76g leads from iirst stage chamber 24. Movement of `diaphragm out of its chamber (upward `in the gure) is opposed by a spring 62h which is chosen or adjusted to allow upward diaphragm movement at, say, aboutl% of the pressure normally existent Ain 24. Upon engine controlled opening of shut-oli 122 diaphragm-62g moves up as soon as the pressure in 24 builds up, and lifts `valve pad 66g to open passage 72g leadingfrom 64g to passage 80g from which tube 78g leads'to reference chamber 50d. Passage or port 72g is adjusted by needle valve 74g. j

As soon as the pressure `in 24 builds up `and the valve at 66g opens, the .action of raising the pressure in 50 and 36 isthefsame as described in connection with e.g. Fig. 1.` .On engine stoppage and closure of shut-oli? 122 only a small` part of `the pressure in 24 can leak ot through 78g, 'valve 66g closing when that pressure is down to, say, 80% of normal.

1 Fig. `7 shows a modification of Fig.. 4, in which th t manifold connection passage 82 tothe valve 60 is dis-y engine controlled opening of cut-0E The regulator is shown' v :151. pensed.. fwith. The: parter1 similarto thosegof Fig.I 4` are given thesame numerals.l l Y .4 Y In this gure the control valve 6014 has a diaphragm chamber-641- that is open to and in eifect forms part of chamber 80]c to which passage 78 connects and leads to reference chamber 50. The back side of` diaphragm 62f is exposed to: atmospheric pressure. The diaphragm carries a pin 66f, that, on diaphragm movement into chamber 64f (down in the gure) pushes on spring 70c to move valve pad 66C off its seat and open pass-age 72C to chamber 80f.

On engine turn-oven the depression, relative to atmospheric pressure, in air intake 14 due to the obstruction,1.5,.is communicated to diaphragm chamber 64f via the balance tube 52, reference chamber v50 'and tube 78. Valve' pad 66o is thus moved off its seat by, downwardv diaphragm movement, and pressure 'gas is admitted from 76 to reference chamber 50 to raise the pressurethere. and the. delivery pressure in 36` to whatever pressure is desired relative to the pressure inV air intake 14.

In Fig. 7, the passage 82C is shown comingfromfthe air intake, as has been remarked before. j

The valve 60f of Fig, 7 may also be set to act as a safety valve to relieve excessively high pressure in chamber 24 in the event of leakage in the valves controllingV feed to that chamber. In Fig. 7 the valve closing spring '10c may be set or chosen to close the valve `at l66C against a pressure, in 72C, of somethingk above the normal pressure in 24. That abnormal pressure under which the valve will be pressed open may be, eg. fteen p.s.i. if the normal pressure is 7 or 8 p.s.i. The samev is.v true of the valves generally denoted 60l in the other figures, wherev the valveclosing springs may be set or 'adjusted to open on any abnormal pressure building up in, 24. Such relief action protects the regulator 'against abnormal pressures. y, Y

Fig. 9 shows another modification similar in certain respects to Fig. 5. In this form of Fig. 9 the referenceA pressure chamber 36d is divided off from chamber 36 by wallA 36e with bleeder port 361, as in Fig. 5. Howeven/ instead of applying positive pressure to 36dv as in Fig. 5, negative pressure is applied -as now described. AJnorzzle 100 dischargesl Ia pressure stream from the high pressure source into` an ejector space 102 with' which chamber A36d communicatesrvia'a port 104; ,'1g`he'feedof pressure gas to nozzle 100 is here shown typically asI via Athe tubes 76 and78 controlled by alvalve 60 and, needle adjustment 74. The valve 60 maybe any of the valves as heretofore described Aas 60, 60a, etc. and controlled in any of the mannersV before described. Or, it may be a simple needle adjustment, asin Fig. and if so, shut-off 122 must be used to shut olf the` initial ,fuel feed. As in the other gures, two controlled valves, 60 Iand 122, may be used, or only one. Controls;v for the valve or valves may be any of the controls 'here kde-v scribed. y AIn this Fig. 9, the normal delivery pressurecf the regl;- ulator will typically be lower than Vthat desired for op.V eration. The valve 40o may be biased towardl closing, as by closing with the pressure in 24. The function of; the ejector `action is then. to lower the pressure in 36d by `the ejector `action at 100, 104, to cause diaphragml 38 to move to the right to open valve 40a and raise the pressure in 36. The restrictions at needle. 74 and at bleed orifice 3,6]c regulate the amount of the. delivery pressure increase. Y i

Fig. shows another modification of Fig. 5'; the parts in Fig. 10 that are the same as in Fig. 5 being given the same numerals. In Fig. 10 a passage tube 716g receives pressure from 24 under adjustment control of needle 74g and ,goes to the control valve indicated at 60.` 'Valve 60 may be` any of-the engine controlled valves 60, 60a', etc. heretofore described.- From valve 60 a passage tube 78g `goes toreference. chamber 36d. Needle `v74g also controls pressure.4 feed fromA 241el a passage,V tube.

eration here. described; Valve 122 may beV used here bfutis. not. necessary to shut on' the regulator.

As.A in. Fig:` 5,.,-regulator valve 40 may be biased open.` Withvalvc, 60- opened under engine control, pressure is,` fedfrom 24: toI 36d with thel same operative result asl in Fig. 5.l The pressure inf/6g, 76h and chamber-120` is then considerably lower than in 24so that. the, valve closingpressureyexerted by diaphragmA 122 is; less than the valve openingypressu-re on, valve 4.0.y Whenv valve;

6 0 closes, under engine controlthe pressure in chamber 12,0immediatelyy builds up to that in 24; and, diaphragm 122. being larger thanvalve 40 the valve is immediately forced closed,` thusA closing all discharge passages leading from.2,4. Y

The` biasing spring; 38a, which` may be used in any ofV the system forms, here described to give a starting fuel pulse, may be; a bimetallic thermostatic spring arranged: to be stiffer at lowA temperatures and less stiif at higherv temperatures. Regulators suchy as here described are` usually'installed inclose proximity to the engine and warm; up as they engine warms up. The bi-metallic spring wilh thenA exert.greater-valve'opening pressure vvhen the enf gine is cold, andl less or none when the engine is: warm.

The valve ofA Eig. 4- may also provide a starting pulse.; For that4 purpose valve stem 66d may fit loosely in the bore through 1wal1'602. Atmospheric opening` 62dv is then` sized to,slow4 the downward movement of diaphragm 62a. Tube 82, being sutliciently large to apply operating depression to chamber 64e onstarting turnover in spite of the leak around the; valve stern, diaphragm 62e moves downr at a regulated rate and opens valve 66e before seat? ing valve 66e.. While 66e is openY and before 66e closes:y

. fuel fromy e Hows through the leak and through 82 to.

the carbureter passage to provide the starting fuel pulse.l

In. any of the'forms, for instance in Fig. 4, *where the valve structure 130. is used to provide a starting fuel pulse,y the calibration at 84 should be larger than hasV been der scribed in connection with Fig. l, or eliminated;l so as to, allow the valve 130-to control the size of the restricted calibration.

Fig'. 8 shows. a modied control circuit that may be substituted for anyl of those previously described. In this rnodiecl circuit instead of initially energizing valve 60 and/ or shut-olf 122 from the starter or ignition circuit, a. manual push buttonl e initially closes the circuit from the battery to linesvr 112 and/or 110 leading to 122 and; 60. As soon as the engine turns over or starts the manifold actuated switch 116:1, paralleling 100e, then closes. the circuit` and holdsit closed during engine operation. Or, inthe lforms Where the control valve is opened or held open by manifold, depression, for example valve 60a of; Fig. El, and ifxshut-off 122 is not used or is opened by' engine controlled means` other than electrical circuiting, the push .buttonl maybe used alone and the valve then held open. by the manifold depression.

The purely schematic showings herefdo not attempt t0; show any of the variouspracticalphysical designs eitherv of the regulator, or of the practical physical association of valve 60 and of passages-76 and 78, etc. with the regulator. All. such things may be designed and arranged for simplicity and efficiency of manufacture and operation without departing from the present invention.

As has been stated, the system, controlling thel re`gul-ator delivery pressure, automatically provides fuel in correct proportions for starting, idling, and medium and heavy rangeoperation. And it gives improved results at low Speed logging` with throttle wide` open, and at heavyI acceleration from low speed because of the prees ticallyinstantaneous response of the regulator inits balanced condition.

1."1n a gaseous `fuel feed system for internal combustion engines, said system comprising a carbureter having an air and mixture passage adapted to feed mixture into the intake manifold of an engine, said passage having an air` intake, a venturi throat and a throttle, a gas pressure regulator having a delivery chamber with `a diaphragm subject on one face to the pressure in that chamber, an inlet for said chamber controlled by an inlet valve, connection between the valve and diaphragm such that diaphragm movement toward the delivery chamber causes the valve to open, a reference pressure chamber at one face orf the diaphragm, a bleeding passage communicating the reference pressure chamber to the air and mixture passage, and an outlet for the delivery chamber feeding Vgas therefrom to the venturi throat, the regulator normally delivering to the venturi throat at a predetermined normal pressure; the combination of, a source of gas under a substantially uniform pressure higher than the pressure existent at the carbureter air intake, a pressure feed passage leading from said source to the reference chamber, a normally closed valve in said passage, and means, `actuated by virtue of engine operation, acting to open said valve, each of said bleeding and pressure feed passages 4being restricted, said restricted passages being so related in effective size that, with the normally closed valve open, the pressure in the reference chamber is controllably modiiedvvith relation to that existent in the air and mixture passage, thus controlling the delivery pressure of the regulator.

'2. The combination defined in claim 1, and in 'which the pressure feed passage also leads to the valve controlled-inlet of the regulator, and the normally closed valve controls the feed of pressure to both the reference pressure chamber and the regulator inlet.

3. The combination defined in claim 2, in which the 'normally closed valve is electrically actuated to open, an electrical circuit for actuating the normally closed valve, 'anda switch in said electrical circuit actuated by virtue 'of engine operation. Y 4. The-combination defined in claim 2, in which the regulator comprises two stages, from one stage of which Athe valve controlled inlet to the delivery chamber is fed, in-Which the pressure feed passage controlled by the normally closed valve feeds pressure to said one stage, and in-which the feed passage to the reference pressure chamber leads from said one stage. j l 5. The combination defined in claim 4, and including also asecond normally closed valve controlling the feed passage to the reference pressure chamber, and means actuatedby virtue `of engine operation to open said second valve. l

6. 'The combination Adefined in'claim l, and including a valvular device for varying the restriction of the` bleeding passage, said lvalvular device comprising a port forming a part of the bleeding passage, a diaphragm and structure forming diaphragm chambers at its opposite faces, one of said chambers communicating with said port and the other having a restricted bleeding outlet, and a closure carried by the diaphragm and adapted in one diaphragm position to partially close said port and in another diaphragm position to open said port.

7. Thecombination defined in claim l, in which said reference `pressure chamber is formed between the diaphragm'and a wall lying between the diaphragm and the delivery chamber, said Iwall having a restricted opening constituting the said bleeding passage, the normal delivery pressure of the regulator being above that existent in the air and mixture passage, a second reference chamber at `theface of the diaphragm opposite the delivery chamber, and a balance passage communicating to said second reference' chamber substantially the pressure existent at the carbureter Aair intake. l l

`ture into the intake manifold of an engine, said pas` sage having an air intake, a venturi throat and a throttle, a two-stage gas pressure regulator having a delivery chamber vwith a diaphragm subject on one face to the pressure in that chamber, an inlet for said chamber controlled by `an inlet valve, said inlet fed from the first stage of the regulator, connectionk between the valve and diaphragm such that diaphragm movement toward the delivery chamber causes the valve to open, the other face of the diaphragm being subject tothe pressure existent at the air intake, and an outlet for the delivery charnber feeding `gas therefrom to the venturi throat, the regulator normally delivering at a` predetermined pressure; the combination of, a wall with a restricted` perforation therethrough extending across the delivery chamber to forma second reference vpressure chamber Ibetween the wall and the diaphragm, an initial inlet passage for gas under pressure leading to the first stage of the regulator, a continuously open but restricted passage leading from said first stage to` said second reference chamber, a normallyI closed-valve controlling the initial inlet passage, and

means, actuated by virtue'lofiengine operation, actingto open said valve, the restricted perforation and passage being so related in effective size that, fwith the normally closed valve open, the pressure in the second reference chamber is raised to o'rrabove thatexistent at the air intake. ,f

A9. The combination defined in claim 7, in which the normally closed valve is 'electrically actuated to open position, an electrical `circuit`for actuatingsaid valve, and a switch controlling said circuit actuated by virtue of engine operation. l l 10. The combination defined inclaim 8, and also ,including a spring acting to yieldably hold the inlet valve of the regulator open. A l .I '11. In a gaseous fuel feed syste'n for internal combustion engines, said system comprising a carbureterhaving an air and mixture passage adapted to feed mixture into the .intake manifold of an engine, said passage having airint'ake, a venturi throat and a throttle, a gas pressure regulator having a delivery chamber with a diaphragm forming one of its walls, an inlet for said chamber controlled by an inlet valve, connection between the valve and the diaphragm such 'that movement of the diaphragm4 into the chamber causes the valve to `open, a reference pressure chamber at Ithe face of the diaphragm oppositefthe delivery chamber, a balance communication communicating to the reference pressure chamber substantially the air pressure existent at the carbureter air intake, and an outlet for said delivery chamber vfeeding gas therefrom to the venturi throat, theI regulatornormally delivering .to ythe venturi throat at a predeterminedY normal pressure; the combination of, a source of gas under a substantially uniform pressure higher' than the pressure existent at the carbureter air intake, a pas'- sage leading. from said source to the reference chamber, a normally closed valve in said passage, means, actuated by virtue of `engine operation, acting to open saidvalve, said` balance communication and said last mentioned passage each being restricted, said restricted passages being so related ineffective size that, with the normally closed valve open and with the restricted balance communication acting as a bleed for the reference chamber, the pressure in the reference chamber is raised above that existent at the air` intake causing corresponding raising of the delivery pressure of the regulator.

12. The combination defined in claim 11, in which the engine has a switch controlled ignition circuit, and in 4.which the .means actuated by virtue of engine operation includes electrical circuit means controlled by'said switch. ,s l l f '13.1T11e combination Adefined in. claim 12, and includl15 ingfalso a. controlling switch `in said circuit,meansac tuatedby .intake manifold depressioni. f '14. `'In a gaseous fuel-feed system for internal combustion engines, said system comprising -a carbureter having Van air and mixture passage adapted `to feed mix-f ture into'the lintake manifold of an engine, saidv passage having an air intake, a ,venturi throat and a throttle, a gas pressure regulator having a delivery chamber with a diaphragm forming'one 'of its walls, an -inlet for said chamber controlled by an inlet valve, connection lbetween the valve and the diaphragm 'such rthat movement of the diaphragm into the chamber causes thezvalve toppen, a 'reference pressure chamber at the Aface ,of the diaphragm opposite the delivery chamber,v aibalancecommunication communicating to Vthe 4reference pressure chamber substantiallyY the air pressure' existent at. the carbureter air-intake, and van outlet for said :delivery chamber feedinggas ktherefrom to .the venturi throat, ,the regulator normally' delivering to the venturi throat at a .predetermined normal pressure; `the combination yof, a source of gas .under `a substantially `uniform pressure higher than the pressure existent at thelcarbureter air intake, a vpassage leading `from saidsorce tothe treference chamber, a normally closed valve in'fsaid passage, means, actuated'rby engineintakemanifold depression, acting to open said. valve, said balance communication and said last-'mentioned passage .each being restricted, said restricted passages being `so related infeifec'- tive size that, with the depression `actuated valve .open and with the restricted balance communication actingas a.` :bleed for the :reference chamber, .the -pressure'in vthe reference chamber is raised abovethat existent at the air intake causing ,corresponding raisingxof the deliveryV pressure ofthe regulator. v v

15. The combination defined in .claim 1,1', :in Vwhich theuengine has .a switch controlled :starting motor circuit, and-.including electrical `means controlled by said switch and acting to open said valve.

16. The combination defined iniclaim 1l, :and ,in which atleast one of the said restricted .passages is adjustable.

17. The combination defined inclaim `14',.and in which atleastone of thesaid restrictedppassag'es is adjustable.

V18. The combination denedin claim 1fl.and=in which the said balance communication `for the .reference chamberconnects with the carbureter air intake .to pick up .the pressure therein and to 4discharge bled-gas finto said intake.

19. The combinationdenedin claim 14and in rwhich the said rbalance:communication for the reference chamiber connects with the carbureter airV intake lto fpick `up ,the :pressure `therein :and to .,'dischargelbled gas into .said intake.

20. The combination defined -in vclaim 1,1, in which .the regulator Iis of )the multiplefstage type .with the said .delivery chamber`,-diaphragm and diaphragm .operated Avalveconstitutin-g `itslast stage,: and in :which `apreced- 'inggstage constitutes the said source of gas under a vsubstantially uniform pressure. 1

V21.. The combination defined in claim 20,1and also including a second normally Lclosed valve .controlling `the initial feedof. gas to thepreceding stage,.and means .actuated .by virtue Aof .engine operation vacting .to open -said second valve. l Y 22.. In a gaseous fuel .feed system 'for vinternal corn- .bustion engines, ysaid system.comprisingfacarbureter hav ing an rair and mixture passage adapted to .feed mixture -into the intake manifold. of'an engine, said passage having `:an air intake, a venturithroat and a throttle, a'gaspr'essure regulator ha-ving aldelivery :chamber-'with a diaphragm forming Vone of its walls, an inletfor said chamber Vcontrolled by Van inlet'valve, connection between the .valveand the diaphragm such thatmovementof the diaphragm intothechamber causes` the valve toppen, areference pressure chamber at the face of the diaphragm VQpi'msitelthetielivery. chamber, a balance :communication communicating; t9, the reference. pressure, chamber sul s-tantially the air pressure existent at the carbureter take, and an outlet for said delivery chamber feeding gas therefrom to the venturi throat, thev regulator vnormally delivering to the venturi throat at a pre-determined normal pressure, and an ignition circuit Vfor the engine; the combination of a source of gas under a substantially form pressure higher than the pressure existent at the carburetor air intake, apassage leading from said source to the reference chamber, a normally closed valve in said passage, electrical circuit means connected into the ignition circuit and acting to open said valve whenever the ignition circuit is energized, a normally closed Valvecontrolling initial feed of fuel to the regulator, said electrical circuit means including means acting to open said feed controlling valve whenever the ignition lcircuit is energized, said balance communication and said last mentioned passage each being restricted, said restricted passages being so related in effective size that, with the normally closed valve open `and with the restricted balance communication acting as a bleed for the reference chamber, the pressure in the reference chamberis raised above that existent at the air intake causing (corresponding raising of the delivery pressure of the regulator.

23. The combination dened in claim 11 and in `which the normally closed valve comprises a casing including a diaphragm exposed on one face in a diaphragm chamber to the pressure existent in the reference pressure chamber and on its other face to atmospheric pressure, and valve means opened by movement of said valve diaphragm into its chamber.

24. The combination deiined in claim l and in which the normally closed valve and the means acting to open said valve are incorporated in a valve structure comprising a first chamber forming a partof the pressure feed passage, a normally closed valve controlling admission of gas to said chamber, a second chamber separated from the rst chamber by a wall and communicating with the air and mixture passage to vbe subjected to depression therefrom, a diaphragm forming another wall of said second chamber vand exposed on its outer face to atmospheric pressure, and a stem connected to the diaphragm and extendingthrough the rstvmentioned 4wall to operate the valve.

25. The combination dened inrclaim 24 and in'which .there is a leak port through the rst mentioned wall, the `diaphragm carries a valve closure to close the leak port when the diaphragm moves `to open the iirstmentioned valve, and in which the exposure ofthe diaphragm to atmospheric pressure is restricted.

26. The combination defined in claim 1, in which said reference pressure chamber is yformed between the diaphragm and a wall lying between lthe diaphragm and the delivery chamber, said wall having a restricted opening constituting the said bleeding passage, the normal delivery pressure of the regulator being below that Vexistent in the air and mixture passage, and said pressurefeed passage terminating in a nozzle inejector relation Ato the reference pressure chamber.

27. In a gaseous fuel feed system for internal combustion engines, said system comprising -a carbureter having an air and Ymixture passage vadapted to feed mixture'V into the intake manifold of an engine, said passage 'having an air intake, a venturi throat and athrottle, av gasp-ressure regulator having a delivery ychamber with a diaphragm forming one of its walls, an inlet for said chamber controlled by an inlet valve, connection between the valve and the diaphragm such that movement of thev diaphragm toward `thechamber causes the valve to open, `a reference pressure chamber atthe `faceof the diaphragm opposite the delivery chamber, a balancelcommunication communicating to the V reference pressure chamber s ubstantially the air pressure existent at the carbureter jair intake, and an ,outlet for sa'id `delivery ,chamber feeding gas therefrom to the venturi throat,.the regulator normal- 17 1y delivering to the venturi throat at super-atmospheric pressure; the combination of a restrictedly perforated wall between the diaphragm and the delivery chamber forming with the diaphragm a second reference chamber, a source of gas under a substantially uniform pressure higher than the pressure existent at the vcarbureter air intake, a second diaphragm chamber yand a diaphragm forming one of its walls, connection between the second diaphragm and the inlet valve such that movement of said diaphragm outward of its chamber closes the inlet 10 valve, a normally closed valve and means, actuated by virtue of engine operation, to open the normally closed valve, a passage leading from the normally closed valve to the second reference chamber, passage means leading rom the pressure source to said normally closed Valve and the second diaphragm chamber, `and `a restriction in said passage means.

No references cited. 

